Baby monitoring devices and systems for detection of respiratory failures such as apnea are widespread and typically use piezoelectric transducer sensors embedded in a plate that can be placed under the mattress of the baby bed for sensing respiratory thereof during sleeping. The sensor unit it usually connected via a data communication cable to a control unit which includes a processor for identification of alarming respiratory related situations such as apnea by identifying non-movement of the baby lying over the bed mattress over the sensor unit.
Other monitoring devices and systems are known in the art for monitoring the same and/or other vital signs related parameters such as pulse and/or blood pressure using the same type of sensors or other sensing technologies.
Patent no. EP0514744 by Shtalryd teaches such a system for monitoring respiratory behavior for detecting apnea and outputting an alarm upon detection of breathing cessations using a transducer movement detector.
US patent application publication no. 2008300499 teaches non-invasive monitoring devices for monitoring minute movements made by the body to report the presence or absence of respiration and normal heart rate. The movements being measured are the pulsations made by the normal operation of both the heart and lungs. This is done by converting the body movements into electrical signals with an adapted polymorph-piezoelectric transducer. The electrical signal that is detected is a mixed signal, a signal composed of a lower frequency (breathing contraction) and the higher frequency (heart pulse). The signals are detected by separating the body motions by an adaptive filter that has a break frequency at twice the frequency of the larger body movement signal (breathing contraction). The separate body movement signals operate with associated logic circuitry to allow each signal to be independently measured, recorded, and acted upon to determine if the individual (patient) is undergoing a life threatening experience. Such an event by either signal will trigger an audio and visual display alarm which is attached on or near the patient. The alarm event trigger is also connected to a low voltage detector circuit to indicate that the supply voltage has dropped below an acceptable level.
Patent application no. JPH10295695 teaches a pressure sensing type respiration and body movement sensor, which detests the respiratory movement and the body movement caused by change in pressure applied on the sensor, generally arranged under the breast of a testee in bed. The sound sensor detects the respiration sound such as a snore and is constituted for example, a microphone and a sound conditioner. The recorder which records data obtained from the respiration and body movement sensor and the sound sensor prints or displays the data recorded in a magnetic storage medium or an electric record medium on a display, etc., by a data processing device during or after recording so as to enable the confirmation.